Ekaterina Aleksandrovna Kniazhnina (Russian: Екатерина Александровна Княжнина, 1746–6 June 1797) was an 18th-century Russian poet. Her surname also appears as Knyazhnina. The daughter of Alexander Sumarokov, she was born and lived in St. Petersburg. She married Yakov Knyazhnin in 1770. She was one of the first Russian women to have poetry published in Russian journals. Kniazhnina was the hostess of an important literary salon. Ivan Krylov wrote a parody about Kniazhnina and her husband in 1787, Prokazniki (The trouble-makers).